This invention relates generally to the art of desoldering implements and more specifically to a flexible, replaceable tip for a vacuum stroke, hand held, desoldering tool of the character useful in desoldering and removing components from a circuit board or the like.
Electronic repair or laboratory technicians, research engineers, and hobbiests are routinely faced with the delicate and often difficult tasks of removing or replacing an electronic component such as, for example, a resistor, capacitor, or integrated circuit chip from a printed circuit board. Typically one may not simply melt the solder and remove the soldered lead or lug: the solder tends to stay in place due to its surface tension; and, when the heat source is removed, the solder cools and refastens the element. Techniques of blowing or shaking the solder away while it is in its molten state are manifestly unsatisfactory in the environment of other exposed wiring which could suffer an electrical short from an errant particle of solder. And the problem is severely aggravated by the vulnerability of electronic components and circuit boards to mechanical or thermal damage if the desoldering process is not done quite deftly.
The successful technique of vacuum desoldering has thus been developed to aid in the desired deft removal of the molten solder. The tools for vacuum desoldering may be elaborate electrically operated vacuum pumps or may be relatively simple hand held tubular instruments containing a trigger actuated, spring energized, single stroke solder sucker. An example of a currently marketed such hand tool is disclosed in the co-pending application entitled Portable Vacuum Pump for Desoldering Purposes, Serial Number 627,067, filed July 2, 1984, by William S. Fortune and Robert E. Dallons.
Because of the exposure of the tip end of the vacuum nozzle to the hot solder and, sometimes, corrosive substances, it is highly desireable that the tip element be replaceable when worn unacceptably from its original size or shape. To maximize the service life of such a nozzle element as well as to provide other advantages, it is typically fabricated of polytetrafluoro-ethylene resin known by its trademark Teflon, a property of the Dupont company. Because Teflon is an expensive material and not readily moldable, the nozzle element is preferably made replaceable separately from the remainder of the tip assembly. A molded end cap may be provided to form the front end of the desoldering tool and retain the small, machined, tubular nozzle. Thus in replacing the worn nozzle element, minimum expense is incurred. A tip assembly of this general character is disclosed in United States Pat. No. 4,204,299 entitled Replaceable Tip for Desoldering Tools issued May 27, 1980, to William S. Fortune.
Although the referenced replaceable tip provided a significant advance over the then prior art and is still the most pertinent prior art known to the applicant, the replaceable nozzle element therein disclosed suffers certain limitations when utilized in the environment of the current art: the nozzle element is difficult to replace without damaging or destroying the end cap member, which retains it; although providing some angular, or nutational, flexibility of the nozzle with respect to the body of the tool, it is undesireably rigid in that respect; it is longitudinally rigid thereby, at times, causing damage to circuit elements from contact therewith particularly during the inherent recoil impulse suffered when a hand held, spring actuated tool is used; and maching and molding tolerances preclude a perfect air seal between the nozzle and the end cap elements causing a compromise in the vacuum stroke efficiency of the tool.
Accordingly, it is an object of the present invention to provide a desoldering tool tip assembly which is not subject to these and other disadvantages or limitations of the prior art.
It is another object to provide such a tip assembly which is readily rebuilt by very easily and inexpensively replacing a worn Teflon nozzle.
It is another object to provide such a tip assembly in which there is no significant vacuum leakage between the nozzle and its retainer cap.
It is another object to provide such a tip assembly in which the nozzle element is angularly flexible having a nutational freedom of motion about its connection to the end cap member while maintaining its vacuum seal.
It is another object to provide such a tip assembly in which the nozzle, while flexible, automatically returns to an axially aligned disposition.
It is another object to provide such a tip assembly in which the troublesome aspect of maintaining the inner bore of the nozzle clean and free of solder, flux, and other matter is significantly minimized.
It is a most important object of the invention to provide such a tip assembly in which the nozzle element is softly cushioned in all directions, including axially, whereby the probability of circuit element damage from contact with the nozzle end is greatly reduced.